How to measure a trimpot?

[sonci]

I wanted to replace the amplifier trimpots. According to manual they are 470ohm, but after removing from pcb and measuring it seems they measure a lot more, but since there are 3 legs I'm not sure how to measure them. One leg has letter H and another 3.

 

[merlynski]

A trimpot is a resistor with a movable tap, read this: https://en.wikipedia.org/wiki/Potentiometer
If it is a 470Ω trimpot it should measure 470Ω between the two small pins, if it measures significantly more (or less) it is probably bad. The wiper (middle tab) will measure a portion of 470 to one end pin, and the other portion to the other pin, depending on where it is adjusted. If it is adjusted all the way to one end it will measure 0Ω to one pin and 470Ω to the other. If the wiper does not make any connection to either pin, the trimpot is defective. Potentiometers' pins are frequently labeled 1, 2, and 3, with 2 usually being the wiper (moveable connection).
Note: The manufacturer may have have changed the value of the installed part without changing the schematic or documenting the change publicly.